医学微生物学英文版教学课件：第24章呼吸道病毒

1、Chapter 24RespirovirusesRespiratory virus orthomyxoviridae Influenza virus -ssRNA (segmented) Influenza Paramyxoviridae Measles virus -ssRNA measles (SSPE) Mumps virus -ssRNA mumps Parainfluenza virus -ssRNA upper respiratory tract infectionRespiratoysyncytial virus -ssRNA Bronchiolitis, Pneumonia o

2、thers Coronavirus +ssRNA upper respiratory tract infection SARSCoV +ssRNA SARS Rubella virus +ssRNA rubella ； congenital defects Rhino virus +ssRNA upper respiratory tract infection Adenovirus dsDNA upper respiratory tract infection Reovirus dsRNA (segmented) mild upper respiratory tract infection V

3、IRUS CORE DISEASE Influenza virusSection 1 Comprises influenza A,B and C, viruses.influenza A viruses can infect a variety of different species (aquatic birds, chickens, horses etc) and can cause worldwide epidemics of influenza (occur approximately every 10-20years).influenza B only infects humans

4、and can cause local outbreaks of influenza.influenza C mainly infects humans and can cause mild respiratory tract infections ,but does not cause outbreaks of influenza. Influenza virusBiological characteristics Influenza virus1.Morphology and Structure spherical 80-120nm in diameter Influenza virust

5、he structure of influenza virus 1) nucleocapsid *ssRNA segmented (7- 8 pieces ) *nucleoprotein helical symmetry surround and bind the RNA, type-specific, stable. RNA-dependent RNA polymerase 3) envelope: M1, M2, lipid bilayer membrane, glycoprotein. spikes：HA,NA Influenza virusM1 proteinhelical nucl

6、eocapsid (RNA and NP protein) HA - hemagglutinin polymerase complexlipid bilayer membrane NA - neuraminidase Influenza virusM2 protein12435678M2M1NAHAsegmented - ssRNANS2RNAPB1PB2PA RNA polymeraseNPRNP（ribonucleoprotein ） Influenza virus 2units: HA1 and HA2HA0HA2HA1水解-S-S- HA Influenza virusHemagglu

7、tinin ( HA ) Influenza virus1.be related to the adsorption of viruses (receptor : sialic acid )2. agglutinate human and some animal RBC 3. antigenicity: show great variability Abs to the HA are protective, neutralize viral infectivity. Influenza virusFunction of HANeutralization antibodyHemagglutina

8、tion inhibition antibodyNeuraminidase ( NA ) Influenza virus Function of NA 1.be related to the release of viruses: hydrolyze the terminal neuraminic acid of glycoprotein on surface of cell. 2. to promote the spread of the virus: liquefying mucus 3. antigenicity: variable Ab cannot neutralize viral

9、infectivity Matrix protein M1-be related to the assemble and budding of virus - maintainedthe viralshape - antigenicity stabilization type-specific M2 - ionchannel regulatepHwithin membrane - antigenicity stabilization 2. Repliction cycle 3.Type and VariationBased on antigenicity of NP and M1: -Infl

10、uenza A, B, C. -these proteins possese no cross reactivity among the three typesBased on HA, NA: -subtype -antigenic variation -only type A has designated subtypes Influenza virus Influenza virus* Antigenic drift: which are minor changes based on mutations in the genome RNA. It can not result in a n

11、ew influenza A subtype and usually cause median or small epidemic of influenza.* Antigenic shift: which are major changes based on the reassortment of segments of the genome RNA. It can result in a new influenza A subtype and usually cause large scale epidemic of influenza. Influenza virus Influenza

12、 virus Influenza virus人流感病毒（H3N2）北美猪流感病毒(H1N1)禽流感病毒猪 体 内 杂 交混合型猪流感病毒(H3N2)北美猪流感病毒(H1N2)北美猪流感病毒(H1N1)猪 体 内 杂 交北美猪流感病毒(H1N1)欧亚猪流感病毒(H1N1)猪 体 内 杂 交四种混合型流感病毒(H1N1)墨西哥流感病毒的形成过程 H7N9禽流感病毒的8个基因片段中，H7片段来源于浙江鸭群中分离的禽流感病毒，而浙江鸭群中的病毒往上追溯，与韩国野鸟中分离的禽流感病毒同源；N9片段与韩国野鸟中分离的禽流感病毒同源。其余6个基因片段（PB2、PB1、PA、NP、M、NS）来源于H9N2禽流

13、感病毒。据病毒基因组比对和亲缘分析显示，H9N2禽流感病毒来源于中国上海、浙江、江苏等地的鸡群。4.Cultivation Culture in chicken embryo. Culture in cell culture (non-CPE) Influenza virus 5.Resistance weak -inactivated at 56 30min. several weeks survive in 0-4. - sensitive to dry, UV. - sensitive to ether, lacticacid, etc. Pathogenesis and immunit

14、y spread via respiratory droplets, contact with contaminated hangs or surfaces. virus particles binds to cells of the respiratory epithelium replication cycle 4 6 h cell necrosis, exfoliation clinical features: *respiratory tract symptoms: sore throat, cough *systemic symptoms: headache, fever, myal

15、gias (muscle pains). Influenza viruspathogenesis Immunity to influenza is sub-typespecific. Resistance to initiation of infection -HA antibody Decreased severity of disease and ability to transmit virus -NA antibody ; HA antibodyProtection correlates with serum Ab (IgG,IgM) SIgA Ab in nasal secretio

16、nimmunityMicrobiological detection1.Virus isolation chicken embryo2.Rapid Diagnosis immunofluorescence ; PCR3.Serology hemagglutination inhibition test complement fixation test ELISA Influenza virus Influenza virusPrevention and treatmentVaccine: Whole inactivated virus vaccines -including H1N1,H3N2

17、 and a B subtype.Treatment chemical agents amantadine; ribavirinchinese medicinal herb radix isatidis; indigowood Influenza virusAvian InfluenzaBlong to type A influenza viruses;can infect birds, pigs, horses, seals and whales, Avian influenza infections in humans: 1997: Hong Kong, (H5N1) 1999: Hong

18、 Kong, H9N2 2003: Hong Kong , H5N1 2003: Netherlands, H7N7 2003: Hong Kong, H9N2serotypes including H5 and H7 are associated with disease in poultry. Influenza virus Influenza virusSARS-associated coronavirus (SARS-CoV)A novel coronavirus;60-220nm, +ssRNA(29.7kb), enveloped. Transmission: close person-to-person contact Associated diseases: Severe Acute Respiratory Syndrome (SARS)中东呼吸系统综合征冠状病毒（ MERS-CoV ）中东呼吸综合征(Middle East respiratory syndrome, MERS，又称“新非典”)是2012年9月发现的一种由新型冠状病毒引起的急性呼吸